Compression Technology

Arm Mali compression technologies are a set of technologies developed by Arm that are integrated into Mali GPUs to enable devices to run smoother, quicker and more reliably. These compression technologies consist of Arm Frame Buffer Compression (AFBC) and Adaptive Scalable Texture Compression (ASTC).   

Adaptive Scalable Texture Compression (ASTC) technology has been adopted as an official extension to both the OpenGL and OpenGL ES graphics APIs. ASTC is a major step forward in terms of image quality, reducing memory bandwidth and thus energy use.

ASTC offers a number of advantages over existing texture compression schemes:

• Flexibility, with bit rates from 8 bits per pixel (bpp) down to less than 1 bpp. This allows content developers to fine-tune the tradeoff of space against quality.
• Support for 1 to 4 color channels, together with modes for uncorrelated channels for use in mask textures and normal maps.
• Support for both low dynamic range (LDR) and high dynamic range (HDR) images. Support for both 2D and 3D images.
• Interoperability: Developers can choose any combination of features that suits their needs.

ASTC specification includes two profiles: LDR and Full. The smaller LDR Profile supports 2D low dynamic range images only. It is designed to be easy to integrate with existing hardware designs that already deal with compressed 2D images in other formats. The LDR Profile is a strict subset of the Full Profile, which also includes the 3D textures and high dynamic range support.

ASTC Blogs

The Arm Frame Buffer Compression (AFBC) protocol addresses the difficulty of creating increasingly more complex designs within the thermal limit of a mobile device. One of the most bandwidth intensive use cases is video post processing. In many use cases, the GPU is required to read a video and apply effects when using video streams as textures in 2D or 3D scenes. In such cases it reduces the overall system level bandwidth and power cost of transferring spatially coordinated image data throughout the system by up to 50%.

A lossless image compression protocol and format, AFBC minimizes the amount of data transferred between IP blocks within a SoC. Its lossless compression ratios are comparable with other leading standards but with the added benefit of fine grained random access, which importantly allows for the application of AFBC throughout other IP blocks within your SoC design.